The ugly truth

Stress makes women less attractive

A recent study on immune function has shown that being stressed out can affect a woman's attractiveness to the opposite sex. The study found that women who registered higher cortisol levels – known as the stress hormone – were considered less attractive than those with lower levels.

The researchers from the University of Turku in Finland were out to prove a correlation between physical attractiveness and immune function, but instead discovered that stress played a far more active role in how attractive a woman was found.

They photographed 52 good-looking Latvian women with an average age of 20, then vaccinated each for hepatitis B and measured how many antibodies they produced as a result, but found that cortisol measured far higher.

The research team then asked 18 heterosexual male undergraduates to rate the women on their attractiveness and found that higher cortisol levels in the women correlated with how attractive the men found them.

The study further found a link between how much fat each women carried and how attractive they were considered.

Too high or too low amounts of body fat reduced the women's attractiveness. In other words, those who were too thin were regarded as just as unattractive as those were seen as too fat.

However, immune function did not predict facial attractiveness, meaning beautiful women don’t necessarily have a strong immune system and vice versa.

Dr Markus Rantala speculated that, instead, low levels of cortisol could signal health in the female face. This would be consistent with many studies in humans that have found stress has strong negative effects on health, including immune function, heart disease and susceptibility to cancer.

Rantala added that an alternative explanation for the findings is that facial attractiveness indicates reproductive potential, which is mediated partly by stress hormones. In fact, past research has shown that stress interferes with fertility.

Interestingly, the reverse results apply to men. Those who are best at producing antibodies in response to a hepatitis B jab are considered better looking by women.

"It is possible facial attractiveness signals a different arm of the immune defence in women than men and remains to be tested in future studies," Rantala conceded.

Another 2010 study showed that when men were in the company of a beautiful woman, their cortisol levels increased, especially when left alone for five minutes – and even more so if the men believed the attractive woman was 'out of their league'.